We've got this lovely gigantically bright and delicious (metaphorically) device here for review by the name of Samsung Infuse 4G, and one of the neatest things about it is it's one of if not THE first phone to employ a dual-function microUSB port that also works with an MHL adapter (also included.) This MHL adapter makes it so you can output to a universal HDMI cable and thusly mirror your display to a much bigger display such as an HD television. There's a catch though that you might find good or you might find bad - you've got to utilize the second port on the adapter to plug in to a power source for the adapter to function.
Let's talk about how this could be a bad thing first. Using your handheld mobile device as a media center to be displayed through your television is a relatively new concept, and one that, if you ask your humble narrator, seems most excellent when it's a simple interaction between the device and the television. Thus far, devices, (such as the T-Mobile G2x, ATRIX 4G, and Motorola XOOM) need no extra power source to transmit media via HDMI cord to the television. Here comes the Samsung Infuse and it's got this great ability to work with HDMI through its usb port, but it needs for you to be plugged into the wall while you're working it!
On the other hand, doesn't it make sense for the device to also be plugged into the wall so as to assure you you'll be able to play whatever it is you want to play without the handset running out of power while you're playing it. It's brilliant for these manufacturers to have put the 2 jacks in one splitter instead of on the device, isn't it? What's your take?